Spacers for field emission displays are known in the art. A field emission display includes an envelope structure having an evacuated interspace region between two display plates. Electrons travel across the interspace region from a cathode plate, upon which electron emitter structures, such as Spindt tips, are fabricated, to an anode plate, which includes deposits of light-emitting materials, or "phosphors."Typically the pressure within the interspace region is less than or equal to 10.sup.-6 Torr.
The cathode plate and anode plate are thin in order to provide low display weight. These thin plates are not structurally sufficient to prevent collapse or bowing upon evacuation of the interspace region. As a result of the atmospheric pressure, spacers play an essential role in lightweight displays. Spacers are structures incorporated between the anode and the cathode plate to provide standoff. The spacers, in conjunction with the thin, lightweight, plates, support the atmospheric pressure allowing the display area to be increased with little or no increase in plate thickness.
Several schemes have been proposed for providing spacers. Some of these schemes include the affixation of structural members to the inner surface of a display plate, particularly, the anode plate. Such prior art schemes include the heating of the display plate and spacer in order to bond the spacer to the display plate. Such schemes require bonding spacers to the anode plate due to its robustness in heating and oxidizing environments compared to the cathode plate. This method has the disadvantage of spacer misalignment when contacting the cathode resulting in destruction of emitters and shorted column or row conductors. Other disadvantages to prior art schemes include large processing times required to heat display plate and spacers, oxidation of cathode metals associated with high temperatures and elaborate pick-and-place equipment required for spacer placement.
Accordingly, there exists a need for a method of affixing spacers within a field emission display that allows affixation of spacers to the cathode plate, reduces processing times, reduces spacer misalignment and eliminates the need for heating of entire display plate and spacer assembly.